The picture shows the markings. It seems to be a JIABEN FA2-5F-1108X, whatever that may be. Can anyone through more light on this, or find a datasheet? Perhaps if I could read chinese it would be easy.

What is its function beyond a passive switch?

With the help of Google translate, I do now have some information. It offers restart protection when the power supply is interrupted and more. It seems to satisfy EN60947.